Field of Invention
The invention relates to an apparatus for analyzing a test liquid.
Background Information
Such apparatus can be used, for example, for analyzing saliva or urine of a test person. It is, however, also possible that other liquids are analyzed or a sample substance to be analyzed, for example in the form of a solid, is first mixed with a so-called washing-out liquid or is dissolved therein and the test liquid obtained in so doing is subsequently analyzed. The analysis can be used, for example, for the detection of drugs, explosives or other substances such as traces of nuts.
In such analyses, the sample substance, for example in the form of saliva, is first mixed with the washing-out liquid so that a test liquid arises which can be analyzed. The mixture is in particular achieved such that a sample collector with which the sample substance can be received is washed out in the washing-out liquid. The test liquid is subsequently usually prepared. For this purpose, the test liquid can be brought into connection with a reaction partner, for example in the form of gold conjugate. The preparation is also called a so-called incubation. After a fixed waiting period, the test liquid thus prepared is conducted to an analysis element which, for example, contains a test strip which is also called a so-called lateral flow assay. The test strip is acted on at one end by a test liquid which then flows through the test strip and collects in a collection path at the oppositely disposed end of the test strip. The test strip can have a nitrocellulose membrane on which test lines and control lines are arranged which react with the test liquid and on which a reaction and thus the analysis result can be read off. The analysis result can, for example, be read of by means of a special electronic evaluation apparatus and processed.
An apparatus for analyzing a test liquid is described in US 2006/ 0292034 A1. The apparatus has an inlet chamber, a preparation chamber and an analysis element having a test strip. The test liquid in the form of saliva of a test person can be received by a sample collector and introduced into the inlet chamber. The sample collector is in this respect pressed out so that test liquid enters into the inlet chamber. The inlet chamber is displaced in the direction of the preparation chamber arranged beneath it by pressing the sample collector onto the base of the inlet chamber, whereby a volume of the preparation chamber is reduced in size and thus varied. The inlet chamber is displaced so far until the base of the inlet chamber tears and thus a not precisely defined quantity of the test liquid flows from the inlet chamber into the preparation chamber. After a fixed incubation time of approximately 2-3 minutes, a slider arranged between the preparation chamber and the test strip is opened so that the prepared test liquid can move onto an end of the test strip. After a reaction time, the analysis result can be read off on the test strip as described above.
An apparatus for analyzing a test liquid is likewise described in DE 202008 017 883 U1. The apparatus has a preparation chamber in the form of a mixing chamber and an analysis element having a test strip. On the utilization of the apparatus, test liquid is filled from a separate washing-out apparatus into the preparation chamber from where it is conducted onto the test strip after the preparation. So that a specific quantity of test liquid is filled into the preparation chamber, it has a filling level marking up to which a user of the apparatus should fill in test liquid. A monitoring or checking of the actually filled-in quantity of test liquid is not possible.
Against this background, it is the object of the invention to propose an apparatus for analyzing a test liquid which is simple and reliable to handle. This object is satisfied in accordance with the invention by an apparatus for analyzing a test liquid having the features recited herein.
The apparatus in accordance with the invention for analyzing a test liquid has an inlet chamber, a preparation chamber and an analysis element. The inlet chamber is provided to receive the test liquid. Test liquid can be brought from the inlet chamber via the preparation chamber onto the analysis element and a volume of the preparation chamber is variable.
In accordance with the invention, the volume of the preparation chamber can be increased, with test liquid being sucked out of the inlet chamber into the preparation chamber by an increase of the volume of the preparation chamber. On the increasing of the volume of the preparation chamber, a vacuum is generated in the preparation chamber on the basis of which an exactly fixed quantity of test liquid is sucked into the preparation chamber. The sucked-in quantity in this respect corresponds to the volume variation of the preparation chamber. It can thus simply be ensured that a defined quantity of test liquid moves into the preparation chamber, which ensures a defined preparation and thus an exact analysis result. The user of the apparatus is in particular assisted in this respect in increasing the volume of the preparation chamber by exactly a defined degree. For this purpose, for example, a mechanical abutment can be provided which bounds the volume increase or a latching or fixing of a starting position and a preparation position of an actuation element by means of which the volume increase can be carried out.
In this respect the connection between the inlet chamber and the preparation chamber is in particular not always present, but it can rather be interrupted. The connection in particular also only exists then when test liquid should actually be introduced into the preparation chamber. In this way it is, on the one hand, prevented that test liquid moves into the preparation chamber in an unwanted manner in a starting position and, on the other hand, it is prevented that further test liquid can move into the preparation chamber during or after the preparation and can thus influence the analysis result. In this way very exact analyses are made possible.
The analysis element in particular has one or more test strips.
In an embodiment of the invention, in a starting state of the apparatus, a washing out liquid is arranged in the inlet chamber and produces the test liquid when mixed with a sample substance. A starting state of the apparatus is to be understood as an unused state, that is the state before the start of an analysis of a sample substance or of a test liquid. The sample substance can, for example, be designed as a liquid, a solid or any desired mixture of liquid and solid. Examples for sample substances are saliva, urine, blood, swabs from objects or food samples. A separate container for the washing-out liquid, which would have to be separately packed and supplied, can be dispensed with by the provision of washing-out liquid in the inlet chamber. In addition, the handling is particularly easy for the user since he does not have to handle a plurality of containers.
The apparatus in accordance with the invention can have a cover by means of which the inlet chamber can be closed. It is also possible that, in the starting state, a sample collector is arranged at least partly in the inlet chamber and can close the inlet chamber so that no washing-out liquid can exit. It is also possible that an envelope for the sample collector is provided in which the sample collector is stored in the starting state. The named envelope is then in particular designed such that it can be partly arranged in the inlet chamber and thus closes it. The envelope can then also serve to close the inlet chamber after the washing-out of the sample collector and thus prevent an exiting of washing-out liquid or test liquid.
In an embodiment of the invention, the apparatus has a housing with an inner housing space. A preparation element is partly or completely arranged within the inner housing space and bounds the preparation chamber partly or completely. The preparation element can also bound two separate preparation chambers. An inlet element is likewise partly or completely arranged within the inner housing space and bounds the inlet chamber partly or completely. The preparation element and the inlet element are arranged behind one another in an axial direction and are connected to one another so that a displacement of the inlet element in the axial direction away from the preparation element increases the volume of the preparation chamber. A compact design of the apparatus is thus made possible. Since the inlet chamber anyway has to be accessible from outside the housing to introduce the sample substance, the volume of the preparation chamber can be increased by the described design of the apparatus without it itself having to be accessible from outside the housing.
The inlet element and the preparation element in particular each have a hollow cylindrical basic shape so that the named axial direction corresponds to the axial direction of the inlet element and of the preparation element. Diameters of the inlet element and of the preparation element in particular differ from one another so that the corresponding inner housing space is predominantly composed of cylinders with different diameters. The diameter of the preparation element is in particular larger than the diameter of the inlet element so that the housing has an abutment which bounds the axial extent of the preparation element and thus the increase of the volume of the preparation chamber and thus the increase of the volume of the preparation chamber by a defined degree is made possible.
The coupling of the preparation element to the inlet element in particular takes place via a peripheral, inwardly directed groove of the preparation element and a corresponding collar of the inlet element. The arrangement of groove and collar can also be reversed.
The preparation element can in particular have peripheral folds which are pulled apart for increasing the volume of the preparation chamber and thus allow the volume increase. Alternatively or additionally, the preparation element can be composed of an elastic material such as an elastomer or silicone.
So that the preparation element is not also completely displaced on a displacement of the inlet element in a direction directed away from the preparation chamber, a fixing of the inlet element in the axial direction with respect to the housing is necessary. This can be realized, for example, by a peripheral collar at an end of the preparation element which is disposed opposite the preparation element and which contacts a corresponding edge of the housing.
In an embodiment of the invention, the inlet element has an actuation element which is arranged outside the housing. The actuation element is designed so that a force for displacing the inlet element can be introduced via the actuation element. The inlet element can thus easily be displaced and test liquid can thus be sucked into the preparation chamber.
The inlet element and the actuation element are in particular made in one piece. It is, however, also possible that they are designed as separate parts which are suitably connected to one another. The actuation element in particular has the same outer contour as the housing and adjoins the housing in the axial direction.
The actuation element can be displaced or in particular rotated in the axial direction to displace the inlet element with respect to the housing. To convert the rotary movement into an axial movement, that is a displacement of the inlet element, the inlet element has a first thread and the housing has a corresponding second thread. A particularly simple handling of the apparatus is thus possible.
In this respect, the inlet element can have an external thread and the housing can have an internal thread or vice versa. The apparatus can, for example, be configured so that a rotation of the actuation element by 180° with respect to the housing displaces the inlet element so far that the preparation element abuts the abutment of the housing and thus the intended quantity of test liquid is sucked out of the inlet chamber into the preparation chamber.
In an embodiment of the invention, the inlet element can be rotated with respect to the housing from a starting position into a preparation position for increasing the volume of the preparation chamber. There is only a connection between the inlet chamber and the preparation chamber between the starting position and the preparation position. There is thus no connection between the inlet chamber and the preparation chamber in the two named positions. It is thus prevented, on the one hand, that test liquid can unintentionally move into the preparation chamber in the starting position and, on the other hand, it is prevented that even further fluid can continue to flow during or after the preparation and can thus influence the analysis result. Very exact analyses thus become possible.
For this purpose, the inlet element, for example, has one or more passages in the direction of the preparation element. The preparation element has corresponding passages or holes which are arranged so that they are only flush with the passages of the inlet element between the starting position and the preparation position.
In an embodiment of the invention, a film which separates the separation chamber from the analysis element in the intact state is arranged between the preparation chamber and the analysis element. To start the analysis of the test liquid, the film can be pierced by means of a punch so that prepared test liquid can flow from the preparation chamber to the analysis element. A simple and inexpensive design of the apparatus and a simple handling are thus made possible.
The analysis element in particular has the named punch and is pivotably connected to the housing. It can adopt a position of rest and an indication position with respect to the housing, with it being configured and arranged such that, on a pivoting with respect to the housing, the punch of the analysis element pierces the film arranged between the preparation chamber and the analysis element and the analysis of the test liquid is thus started. The analysis procedure can thus be started very simply by pivoting the analysis element.
The analysis element in this respect in particular has a predominantly parallelepiped-shaped basic shape. In the position of rest, a main direction of extent of the analysis element is arranged predominantly parallel to the axial direction. To bring it into the indication position, it is, for example, pivoted or unfolded by 90° with respect to the housing. The analysis element usually contains one or more test strips to whose shape it is matched. In this case, the named main direction of extent extends in the direction of flow of the test strip. The analysis element is in the described position of rest in the starting state of the apparatus. The apparatus is thus very compact in the starting state, in which it is also stored and sold, and is thus simple and inexpensive to store and to transport. The analysis element is in particular arranged so that openings for reading the analysis result are oriented toward the housing in the position of rest and are thus protected.
The pivotable arrangement of the analysis element with respect to the housing is independent of the manner how test liquid is brought from the inlet chamber into the preparation chamber. The described arrangement can thus also be combined with any other possible manner of bringing test liquid from the inlet chamber into the preparation chamber.
In an embodiment of the invention, the apparatus has a housing which has the inlet chamber, an inner housing space, an inflow line from the inlet chamber to the inner housing space and an outflow line from the inner housing space to the analysis element. A plunger with a step is displaceably arranged in the inner housing space. In addition, a ring piston is arranged on the plunger and can be displaced at least piece-wise both in the inner housing space and with respect to the plunger. The preparation chamber is in this case formed by an end face of the named step of the plunger facing the ring piston, by the inner housing space and by the ring piston. The plunger and the ring piston are in this respect configured and arranged such that, on a displacement of the plunger from a starting position into a preparation position, the ring piston first remains stationary with respect to the inner housing space and thus the volume of the preparation chamber is increased. It is not necessary in this respect that the ring piston does not move at all. A small displacement of the ring piston is permitted; however it must be considerably smaller than the displacement of the plunger. This allows a simple design of the apparatus.
So that the ring piston first remains stationary, the individual parts can, for example, be designed such that the friction between the ring piston and the inner housing space is larger than the friction between the ring piston and the plunger. Additionally or alternatively, the inner housing space can have a step which first holds the ring piston in its position. The inner housing space in particular has a predominantly cylindrical shape. Its axis extends in this respect in particular parallel to the main direction of extent of the analysis element. This allows a particularly compact design of the apparatus.
In an embodiment of the invention, the plunger and the ring piston are configured and arranged such that, in the starting position, the inflow line from the inlet chamber is closed toward the inner housing space. There is thus no connection between the inlet chamber and the preparation chamber in the starting position. It is thus prevented that test liquid unintentionally flows into the preparation chamber in the starting position. The inflow line is in this respect in particular closed by the plunger which has a corresponding shape for this purpose and can additionally have sealing elements such as 0 rings.
The outflow line from the inner housing space to the analysis element is in particular closed in the preparation position. It is thus prevented that the test liquid already moves to the analysis element before the end of the preparation. For this purpose, in particular the plunger is also used, with the named or additional sealing elements likewise being able to act.
In an embodiment of the invention, the plunger has a driver which is configured such that it bounds a relative movement between the plunger and the ring piston. The driver is, for example, configured as a region having a larger diameter than the passage of the ring piston. The plunger and the ring piston are arranged in the preparation position such that the inflow line from the inlet chamber to the inner housing space is closed. It is thus prevented that further test liquid can still continue to flow during or after the preparation and can thus influence the analysis result. This is in particular implemented in that the ring piston is taken on so far by the driver, starting from its position in the starting position, that it closes the inflow line. For better sealing, the ring piston can have peripheral sealing lips or additional sealing elements, for example in the form of 0 rings.
In addition, the plunger and the ring piston can adopt an analysis position in which the outflow line from the inner housing space to the analysis element is open and a connection from the inlet chamber to the preparation chamber is interrupted. It is thus made possible that prepared test liquid can move to the analysis element and simultaneously prevents that in so doing still further, untreated, test fluid flows into the preparation chamber. The named connection from the inlet chamber to the preparation chamber is in this respect in particular interrupted by the ring piston and the plunger. It can be possible in this respect that the inflow line from the inlet chamber to the inner housing space is admittedly open, but no test fluid can move from the inflow line into the preparation chamber.
In an embodiment of the invention, the apparatus has an actuation element which is arranged displaceable with respect to the housing, which is coupled to the plunger and by means of which a force can be introduced for displacing the plunger. A simple handling of the apparatus is thus made possible. It is possible that latches are provided between the housing and the actuation element for the secure setting of the different positions, said latches fixing the actuation element in the individual positions, but being able to be overcome by pressing. For this purpose, the actuation element can have one or more cut-outs and the housing can have correspondingly positioned elevated portions.
The actuation element can in particular have one or more cut-outs through which markings are visible which indicate a current position of the inlet element or of the plunger. In addition, information can also be given on corresponding waiting times at the individual positions. A user can thus be informed simply over the current progress of the analysis and his attention can be drawn to possible waiting times which have to be observed. A secure handling and thus also reliable analysis results are thus achieved.
In an embodiment of the invention, the housing has a storage space for a sample collector. All the parts required for the analysis of the test substance can thus be combined together, which allows a simple handling. As already stated, the inlet chamber can serve as a storage space. It is, however, also possible that an additional storage space is provided.
The individual parts of the apparatus can, for example, be composed of polyethylene or polypropylene and in particular be manufactured by means of an injection molding process.
Further advantages, features and details of the invention result with reference to the following description of embodiments and with reference to drawings in which elements which are the same or have the same function are provided with identical reference numerals.